Project Summary/Abstract Avoidable harms due to medical care and high healthcare expenditures are persistent problems among aging adults. To mitigate these problems, improvements in surgical care are essential because surgery accounts for half of all serious harms and 30% of all expenditures. The overuse and misuse of surgery are important drivers of well-documented variations in rates of surgery, perioperative complications, and costs. Overuse occurs when surgeons operate even though the risks to the patient exceed the potential benefits, and misuse occurs when surgeons do not choose the procedure that gives the patient the best risk-benefit ratio. Appropriate use criteria (AUC) are rigorously developed tools for assessing the risk-benefit ratio of a specific procedure for an individual patient. Employing AUC would enable surgeons to avoid inappropriate operations, yet no strategies exist for supporting implementation of AUC in routine practice. Behavioral science ?nudges? are a novel and promising strategy for improving surgical decision making because nudges can predictably influence behavior while preserving autonomy. Our longer-term objective is to test whether surgical appropriateness nudges facilitate routine use of AUC by surgeons, limit overuse and misuse, and reduce surgeon-level variation in major operative complications, using degenerative lumbar scoliosis and spondylolisthesis as examples. Many older adults undergo highly complex, risky, and costly operations for these age-related conditions. Working with major national specialty societies, our team recently developed AUC for scoliosis and another group developed similar AUC for spondylolisthesis. The current project will prepare our team to develop a randomized controlled trial of surgical appropriateness nudges supporting the implementation of these AUC. Specific Aims are: (1) to develop surgical appropriateness nudges for complex degenerative lumbar spine conditions, including (a) to design nudges via collaboration among experts in spine disorders, behavioral science, and informatics and (b) to pilot test the nudges in two health systems and refine them based on spine surgeons' feedback; and (2) to characterize surgeon-level variation in the choice of procedure and operative complications. Achieving these aims will lead to nudges that surgeons at study sites will perceive as feasible for incorporation into the surgical workflow, potentially effective at improving adherence to AUC, and acceptable for use in their own practice. Additionally, documenting baseline surgeon-level variation in surgical practices and outcomes will provide indirect evidence that surgical decision making is probably suboptimal, inform the development of nudges, and facilitate planning for statistical analyses in the future trial. Working closely with specialty societies and two large health systems will facilitate national dissemination of the innovative implementation strategies that we propose to develop. If surgical appropriateness nudges are effective, improvements in decision making and complication rates are likely to lead to better patient-reported outcomes and lower healthcare costs.